Make RGB LED Display with xc-3 kit more Economical

[jsmaia]

Hi All,
First sorry for my bad English. I've been following this tread with great interest. For a long time I've been dreaming of build a Full color RGB LED display and the AN from XMOS helped me a lot to understand how this can be archived. I started buying 1000 5050 RGB leds from China thinking to start with some 16x16 pixels boards. When I start searching for the LED drivers I found SiTI, a Chinese company who have a extensive line of led drives. I bought some DM631 and now I am designing the LED board. For control I thought to use the XC-3 board but I have no way to build boards with BGA parts, so I really apreciate your idea of use LQFP parts.
Thank you all for all informations you are posting here and if you need some of the little help I can give, I will be very happy in participate of this great project
Regards,
Maia

[jagspaul]

Welcome jsmaia.
I have started designing the L1 schematic for Ethernet and LED driver control board. But I am bit confuse with power circuit. I don’t want to use any switching regulator due to unavailability of proper inductor. I am looking for some low cost precision series regulator and reset chip.

I am also thinking to provide a power supply extension connector to send supply (3.3v, 1.0v & reset signal) from Ethernet board to LED driver control board. But I don’t know technically it is feasible or not??

jags

[Interactive_Matter]

Hi All,
First sorry for my bad English. I've been following this tread with great interest. For a long time I've been dreaming of build a Full color RGB LED display and the AN from XMOS helped me a lot to understand how this can be archived. I started buying 1000 5050 RGB leds from China thinking to start with some 16x16 pixels boards. When I start searching for the LED drivers I found SiTI, a Chinese company who have a extensive line of led drives. I bought some DM631 and now I am designing the LED board. For control I thought to use the XC-3 board but I have no way to build boards with BGA parts, so I really apreciate your idea of use LQFP parts.
Thank you all for all informations you are posting here and if you need some of the little help I can give, I will be very happy in participate of this great project
Regards,
Maia

Welcome!

Yes we are currently working on very different aspects of this solution to make it easier to work with.
I think it is pretty safe if you start implementing an DM631 driver. With the current XC-3 solution on the repository you should be able to see some more or less visible XMOS logo. In the time you are there we presumably have this driven much further ;)

You own an XC-3 kit?

If you implement the code please fork directly on github since then I am able to integrate your changes. I still have to merge some changes by me in order to make it working. But that is done very quickly.

I would suggest to open a new forum topic for the DM631 driver.

Regards & welcome

Marcus

[Interactive_Matter]

…

I am also thinking to provide a power supply extension connector to send supply (3.3v, 1.0v & reset signal) from Ethernet board to LED driver control board. But I don’t know technically it is feasible or not??

jags

Hi this is something I would not do. The LEDs draw a lot of power and you would have to route all this power through your board. Or don't you mean the power for the LEDs. I have tested several times to draw power for logic chips from the XMOS boards and this works astonishingly well.
Be sure to add a good amount of capacitance to your led controller board if you do so (100µF or so at the power entry to the board - smaller values should work too, but less than 10µF does not seem to be a good idea for me).
I have experienced some resets every time I plug in a connector, where I am using power (perhaps the voltage supervisor) - but this was never a problem for me.

So digital power no problem.
LED power better not.

[jagspaul]

oh! its ok.
I will share power to xmos controller board only. LED module will get power from different high power bus (5V).
So as per your experience with a single set of series voltage regulator we can provide power to multiple L1 controller board. It is relay good. we can save large amount from poewr & reset circuit.

jags

[Interactive_Matter]

oh! its ok.
I will share power to xmos controller board only. LED module will get power from different high power bus (5V).
So as per your experience with a single set of series voltage regulator we can provide power to multiple L1 controller board. It is relay good. we can save large amount from poewr & reset circuit.

jags

I just said for general digital chips. I do not have any experience powering several L1 controllers from single power lines ;)
I think the 1V control line and the power sequencing can be problematic. If the voltage comparator says that 1V is fine on the first board and reset can be released it may be that the same situation is not true for the other boards dangling from those lines.

I personally would share 3.3V but keep 1V and reset circuitry locally. Especially to reduce noise in the power lines. But this is just how I would be doing it - I have never done it.

Hope that helps

Marcus

[nisma]

Can you give a indicative cost for the DM631 .
I´m currently working on a VM for the Xmos cpu that have higher priority.
For the ethernet board, this can be simulated with the xtag-2 if you have one,
or in case you don´t need ethernet and usb is ok, the xtag works fine and is cheap.
Sure, it have only one xlink and not two so it is more limited.
Annother point, the Xtag-2 could drive the led-panel too if you need it for testing.

[jagspaul]

give some part number of low cost precision series regulator of 3.3v & 1.0V and reset ckt chip

jags

[jagspaul]

Please note that shift register part of DM631 is totally different with MBI5030/31 so without modifying LED driver code you can not run existing LED tile source with DM631 LED driver.
In this case if you need I can help you.

jags

[jsmaia]

Hi All,

jags: Yes, I know I have to modify the/write a new code for DM631. I wrote a routine for a LPC1768 to drive a DM631 and it is working well in the tests. No dificulty here.

nisma: The cost is (for low quantity)
DM631, 1A, 2, 2A, 2B = US$0.77
DM634 = US$0.61 <- I´m thinking using this

Marcus: I don´t have the kit os any XMOS part. I´m from Brazil and is so expensive to buy few parts from Digikey. They charge US$40 for shipping and the customs here charge 100% over parts + shipping costs. As an example, if I buy 4 US$7.00 XL-1 parts, I will have to pay US$136.00. If some have some XMOS spare parts and want to sell I will very happy to buy. :D We can use a less expensive shipping way and if you send as 'gift' the customs don´t charge the duty taxes.

Thank you all for responding.

Best regards,
Maia

P.S. I'aml learning English, so if someone could corret my text I´ll be very thankful.